Contact adhesives natural rubber based

Contact adhesives. Natural and synthetic rubber-based contact adhesives are used for bonding various interior decorative materials such as fabrics and decorative laminates to underlying surfaces. 

Contact Adhesives. Nowadays, rubber solutions based on natural rubber or styrene-butadiene rubber, optionally in conjunction with regenerate and depolymerized rubber, are used for large-area bonding where adhesion does not have to meet stringent requirements, as is the case, for example, with the lining of vessels, containers, etc. with rubber. 

Solvent cements encompass a wide range of performance properties, from the simple natural rubber based cements which are widely used for low performance applications in homes and schools to the structural applications of contact adhesives based on polychloroprene and reactive phenolic resins. 

Some rubber base adhesives need vulcanization to produce adequate ultimate strength. The adhesion is mainly due to chemical interactions at the interface. Other rubber base adhesives (contact adhesives) do not necessarily need vulcanization but rather adequate formulation to produce adhesive joints, mainly with porous substrates. In this case, the mechanism of diffusion dominates their adhesion properties. Consequently, the properties of the elastomeric adhesives depend on both the variety of intrinsic properties in natural and synthetic elastomers, and the modifying additives which may be incorporated into the adhesive formulation (tackifiers, reinforcing resins, fillers, plasticizers, curing agents, etc.). 

Natural rubber adhesives were traditionally used as contact adhesives. However, synthetic polymers are more generally used today. Polychloroprene adhesives are the most common contact adhesives based on synthetic rubber, although recently some have been displaced by polyurethane and acrylic polymers [2]. 

Recently, Caster et al. described the surface modification of multifilament fibers such as nylon or Kevlar [70]. Coating techniques using preformed ROMP-based polymers and process contact metathesis polymerization (CMP), initially described by Grubbs et al. [71], were both used. The latter involves a procedure where the initiator is physisorbed onto the surface of a substrate and fed with a ROMP-active monomer that finally encapsulates the substrate. These modified fibers showed improved adhesion to natural rubber elastomers. 

Because of its excellent high- and low-temperature properties, many products used in the arctic and tropical areas of the world are made from natural rubber. However, it is not suitable for applications where there is contact with naphtha, e.g, gasoline hoses, because the solvent swells the material. Almost all clastic bands arc made from natural rubber. Because of its excellent tack properties, the material is used in solvent and latex form as the base for adhesives. 

Synthetic rubber, a dimethylbutadiene, was developed as a substitute for natural rubber in Germany during World War I and saw limited use as an adhesive. In the early 1930s, neoprene rubber (then called Duprene) became available to adhesive manufacturers in the United States, and shortly thereafter in Great Britain. Today, neoprene rubber adhesives are available as both thermoplastic and cross-linking systems in both solvent and emulsion formulations. Neoprene rubber is the major base resin for contact adhesives. A limited amount of neoprene rubber is also used in sealants. 

Rubber-based adhesives, also called elastomeric adhesives, is probably the most commonly known family of adhesives for industrial and household applications such as pressure-sensitive tapes and labels, construction, contact adhesives, hot melt packaging and bookbinding, and high-strength structural applications for aircraft, automotive and construction. In fact, about one-third of the adhesives used in the world are made from natural or synthetic rubbers. This article gives a general introduction. More specific aspects can be found in further articles listed at the end. 

The most typical adhesive solvents are those based on elastomers, compounds characterized by the fact that they have a strong natural adhesiveness, especially in respect of themselves (the phenomenon of self-adhesion, the instantaneous adhesion of two films of glue after almost total evaporation of the solvent, is the basis for the composition of the contact glues especially neoprene-based (Fletcher 1971)). The basic chemical composition of neoprene synthetic rubber is polychloroprene (O Fig. 14.6). The polymer structure can be modified by copolymerizing chloroprene with, for example, 2,3-dichloro-1,3-butadiene to yield a family of materials with a broad range of chemical and physical properties. 

Water-based dispersion adhesives consist of oligomers dispersed in water with surfactants as dispersing agents and stabilizers. Before dispersions, natural rubber latex and casein were used to manufacture such adhesives. Currently, polyvinyl acetate (PVAc) and polyacrylate serve as synthetic base polymers for water-based PSA, while polychloroprene and thermoplastic polyurethane serve the same purpose for water-based contact adhesives. 

Other substances with which adhesives may come into contact include a variety of chemicals, the most common of which might be oils. The type of glues most likely to suffer in this case would be those having an affinity for that sort of oil, whether it be vegetable or mineral in origin. Motor oil for instance rapidly softens certain rubbers, including natural rubber, so adhesives based on them would be weakened. 

Chem. Desaip. Silicone-based, protein-supported emulsion Uses Dewebber, defoamer, antifoam for natural and syn. latexes in latex dipping industry (mfg. of toys, medical, household, and industrial gloves, anesthesia bags) defoamer for pulp/paper mfg., influent and effluent wastewater treatment, boiler water treatmenL paints, adhesives, and sealants food-contact rubber articles Regiiatory. FDA 21CFR 177.2600... 

Uses Tackiflerfor SBR, natural mbber, butyl mbber, ethylene-vinyl acetate and other polymers, water and solv.-based constmetion adhesives, pressure-sensitive, sealant, hot-melt and rubber compding. tbod-pkg. adhesives, rubber articles defoamer In food-contact paper/paperboard Regulatory FDA 21CFR 175.105,176.210,177.2600 Properties Gardner 9 flakes, solid, or soi n. sol. in aromatic, aliphatic, and chlorinated soivs. sol. > 50% in ethanol, propanol, IPA insol. in water dens. 8.8 Ib/gal vise. (Gardner) Z (75% in min. spirits) soften, pt. (R B) 80 C acid no. 140 Has Unitan-L [Universal Preserv-A-Chem]... 

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